In an aircraft, the outer skin is spaced from the walls and ceiling of a passenger cabin (or other compartment), and the gap is at least partially filled with an insulation layer or blanket. The insulation layer is typically formed from a waterproof material. During a flight, liquid from moist air can condense against the skin and freeze during cruise. During decent, this frozen liquid can thaw and drip back down towards the cabin. Because the insulation blanket is waterproof, the condensate can flow along the insulation blanket and drain into the bilge. However, at some locations, structures and/or supports can protrude through the insulation blanket. For example, the supports that hold monuments and bins to the crown extend from the structure at the skin, through the insulation blanket, and into the cabin. The insulation blankets come with predefined holes for the supports to extend through the blanket. The holes are lined, and there may be a gap defined between the inner surface of the hole and the support. When liquid thaws, it can drip down through the hole and into the cabin.
One previous attempt to fix this problem was to wrap the support in felt so the felt will absorb the condensate and allow the condensate to evaporate back into the air. However, the condensate may be more than the felt can absorb. Further, wrapping each support in felt can be time-consuming.